Energy conservation and climate change mitigation have fostered the development of alternatives to the direct use of fossil fuels. Light to electrical energy conversion in the form of solar panels is one alternative but this has limitation due to:                a. The large area required for efficient generation in urban areas so that the real estate available is mainly confined to residential or building roofs.        b. The remote geographical locations of the regions with the optimal days per year of sunlight so that the power transfer losses for connecting to the National Power Grid become significant.        
Electrical energy generated by conventional wind turbines has similar limitations. In contrast the present invention takes advantage of existing real estate to provide dual use; moreover, the power is generated close to potential usage sites and users. One valuable source of energy is that generated by the movement of vehicular traffic. For combustion engine vehicles the engine reaches sufficient temperatures that the heat must be dissipated usually with a coolant system although for smaller engines air cooling will suffice. For a conventional automobile powered by internal combustion, the energy efficiency is about 20% with the remaining 80% dissipated as heat. Some of the kinetic energy can be harvested and some of the frictional heat avoided with the present invention.
Vehicular traffic generates and then dissipates energy in at least four forms.                1. The weight of the vehicle exerts pressure on the surface over which it passes. In the United States the average car, SUV or light truck, according to the US Department of Transportation, weighs approximately 4000 lbs (1814 kg). Assuming uniform distribution of weight, each wheel of a four-wheeled vehicle supports 1000 lbs (454 kg). With a contact surface of 32 square inches (206 square centimeters) the pressure would be 21.5 newtons per square centimeter. A portion of this pressure differential is harvested with the Piezoelectric Sensors of the present invention.        2. The translational kinetic energy of a moving object, E sub t, is ½ mv2. So the energy possessed by a 4000-lb (1814-kg) vehicle traveling at 60 mph (27 m/s) is ½ (1814) (27)2 or 1.32 million joules which in electrical terms is equivalent to 367 Kilowatt-hours. There are 250 million such vehicles in the United States so if all were in motion at highway speeds they would constitute 91.8 billion Kilowatt-hours which is the electrical energy sufficient for 8.3 million homes for an entire year. In heavy traffic around any major city or on the major highways several hundred vehicles may pass by a single point in a given hour so the energy harvesting potential is significant. But that energy is dissipated usually in the form of heat when the vehicles brake (see below). If some portion of that energy could be recaptured rather than dissipated, the savings would be considerable. The linear or rotational displacement of the vehicle over the surface on which it travels exerts an equal and opposite force between the vehicle's wheels and the surface. A portion of this force differential is harvested by the Electric Generator of the present invention.        3. A vehicle's motion displaces its surrounding fluid even when drag is minimized through efficient aerodynamic design. According to the US Energy Information Administration on average 5.3% of the energy required to move a vehicle is needed to push the air off the path of the vehicle. The motion of the displaced fluid outside the laminar flow zone around a vehicle presents a source of energy to be harvested by the present invention as described in the second preferred embodiment.        4. As a vehicle slows or brakes to a stop the kinetic energy is typically dissipated as heat. However, such kinetic energy can be harvested by the present invention as described in the preferred embodiments.        
The present invention is a power-recapture method and system for converting mechanical energy that would otherwise be dissipated into available electrical energy. Said invention teaches an innovative and comprehensive approach to energy harvesting from vehicular and ambient motion and has advantages over prior art by deploying the system in close proximity to energy-consuming users and devices.